1. Field of the Invention
The present invention relates to a method and apparatus for vehicle path tracking and more particularly relates to a method and apparatus for vehicle path tracking with error correction.
2. Description of Related Art
Advanced-Driver Assistance System (ADAS) is a significant foundation of autonomous vehicles. For example, obstacle detection, assistant driving determination, and communication between vehicles or within the vehicle are significant sub-systems in the ADAS. Many different sensors are used to gather information within the vehicle itself, traffic information, and so on. An electronic controlling unit is used to analyze the information to generate corresponding signals.
With reference to FIG. 9, a conventional control flow diagram for vehicle path tracking is disclosed. As shown in FIG. 9, a controller 100 in the ADAS may obtain a real vehicle driving path in accordance with a known target path 200 and a feedback. The controller 100 compares the target path 200 with the real driving path to obtain an error between the target path 200 and the real driving path, and calculates a turning angle according to the error so as to control the vehicle to adjust a moving path appropriately by the turning angle. The goal to perform the aforementioned adjustment is to keep the vehicle following the target path 200 to move.
With reference to FIG. 10, when the vehicle automatically adjusts its driving path in accordance with the conventional control flow diagram in FIG. 9, a moving path in a first correction path 310 or a second correction path 320 may happen in reality. In one condition, the first correction path 310 represents that the vehicle is obviously away from the target path 200 when the vehicle changes the path during the correction procedure and the correction procedure is too late. In another condition, the second correction path 320 represents that the vehicle changes the path too much during the correction procedure and the vehicle has to perform the correction procedure one more time to move back to the target path 200.
The reason of the occurrence of the problems shown as the first correction path 310 or the second correction path 320 in FIG. 10 is that the controller 100 only compares the error between the target path 200 and the real path without considering dynamic variation of the vehicle during the correction procedure. When the moving path of the vehicle is as shown in the first correction path 310 or the second correction path 320, the movement of the vehicle occurs obviously and frequently in a short time. The passengers in the car may feel uncomfortable and the risk of the rollover of the vehicle may happen.